Process for obtaining soap



Patented Oct. 22, 1929 mm STATES PATENT-&-0FFICE emoonr rnrnorr, or irescommussra This invention relates to processes of pre- 7 paring hard soaps and soap powders from vegetable and animal fats in the nature of drying and semi-drying oils, and it comprises a process in which such oils,*prior to saponification with alkalies in the usual way, are

treatedwith water-insoluble salts of chromic acid in the presence of an acid other than chromic acid which is capable of forming water insoluble salts with the metallic radical of the chromate used.

Many drying and semi-drying oils are i totally unsuited for soap making purposes .due to the fact that these oils, on saponification in the usual wa yield soft or liquid soaps. In the arts, hard soaps, such asthose made by saponifying solid fats which on sapon'ification yield salts of stearic acid and other fatty and non-drying acids, capable of forming hard soaps, are more desirable. Soft soaps have but limited utility because of their physical nature.

- It is'an object of this invention to so treat drying and semi-dryingv oils such as linseed, sunflower, cottonseed oil, etc., that these oils,

normally unsuitable for soap making, may be converted into substances which, on saponifi-- cation in the usual way, are capable of giving hard soaps and soap powders. Withoutlthe preliminary treatment I have discovered, such drying and semi-drying oils, as is well known, yield greasy and smeary soaps unfit I find suitable sulfuric, phosphoric or other acids yielding insoluble salts of calcium, barium or lead.

In general, he drying or semi-drying oils are treated with an insoluble chromate and a precipitating mineral acid, such as sulfuric and phosphoric and the resulting mixture alrnocnss r03. on'rammo soar No Drawing. Application filed January 16, 1926, Serial No. 81,833, and in Germany December 21, 1925.

x lowed to stand for a few hours. The mixture stratifies and the bottomlayer, whichco'nsists of an aqueous solutionof the mineral acid and the insoluble salt of this'acid, is drawn off. 1

The oil layer is washed with water and thereafter saponified in the usual way.

In saponifying the treated oil, the washed oil is either boiled or simply mixed in the cold with an aqueous alkali solution in such quantity that all the fatty acids contained in the oil (which may in part be in the form of glycerides) are neutralized, that is, converted into alkali metal salts. The saponification step is the usual one employed in soap making.

As a specific example of an advantageousway of carrying out my process, I introduce into a closed vessel or tank 100 parts of sun- ,flower oil, 2 parts of barium chromate, 5

parts of 30 per cent sulfuric acid and 30 parts of water. These'materials are mixed insthe cold, or at ordinary temperature (10 to 30 C.) and allowed to stand over a period of 10 to 5 hours. The bottom layer, the mixture having Stratified, is drawn 0H and the oil layer washed with water. The bottom layer consists of dilute sulfuricacid and fsettled barium sulphate. The oil layer consists of sunflower oil which presumably has been "oxidized to some extent, since sunflower oil,

in common with other drying and semi-drying oils, is unsaturated. The exact phenomena occurrin however is not clear. I content myself w1th noting the fact that drying and semi-drying oils, when subjected to the above treatment, give hard soaps on saponification. The so prepared washed oil is then saponified with 50 parts of a30 per cent solution of caustic soda. This sa onification step is well known in the art an may be carried out in the usual-way,.either in the cold or at an elevated temperature.

I have further found that hardsoaps so prepared from drying and semi-drying oils powdered metal is added. The amount to be added is only that required to prevent the darkening of the soap on standing. Oneareimproved if to the soap, or during saponic fication of the oils, a small quantity of a tenth of one per cent based on the soap is usually suflicient and powdered zinc and aluminum are advantageously used. These metals act to inhibit any oxidation of the soap on exposure to atmospheric influences.

Various fillers ma be added to the soap, such as finely divide clay, cellulose, etc. as is customary.

What I claim is:

1. In the process of preparing hard soaps from drying and semi-dryin oils, the step which comprises treating t e oil with a water insoluble metallic chromate in the presence of a mineral acid other than chromic capable of forming water insoluble salts with the metallic radical of the chromate used.

'2. In the process'of preparing hard soaps from drying and semi-drying oils, the step which comprises treating the oil with an al 'kaline earth metal chromate in the presence of a mineral acid other than chromic capable of forming water insoluble salts with the alkaline earth metal.

3. In the process of preparing hard soaps from drying and semi-drying oils, the step which comprises treating the oil with a water insoluble chromate in the presence of sulfuric acid.

4. In the process of preparing hard soaps from drying and semisdrying oils, the step which comprises treating the oil with barium chromate in the presence of sulfuric acid.

5. In the process of preparing hard soaps from drying and semi-drying oils, the steps which comprise treating the oil with an alkaline earth metal chromate in the presence of a mineral acid capable of forming water insoluble salts with the alkaline earth metals, allowing the mixture to stand, drawing otf the stratified lower aqueous layer, and washin the oil.

n testimony whereof I have signed my name to this specification.

GRIGORI PETROFF. 

